Derivatives or adducts of PIB useful as fuel and lubricant additives are known in the art. U.S. Pat. No. 7,091,285 to Baxter et al. discloses adducts of mid-range vinylidene PIB for use as additives in fuels and lubricants. The products are prepared with polyisobutylene having a vinylidene (alpha) content of less than 70% and where the polydispersity of the polyisobutylene is no more than 2. Polyisobutylene is reacted with maleic anhydride, a phenolic compound or another compound having a reactive site for subsequent amination.
U.S. Pat. No. 6,884,855 to Nelson et al. discloses sulfurized polyisobutylenes useful as lubricant additives, specifically wear and oxidation inhibitors. The materials are prepared by reaction of polyisobutene with a sulfur compound at elevated temperatures and low pressures.
U.S. Pat. No. 5,124,484 to Brown et al. discloses a process for producing polyisobutene amines by reacting carbonyl-functional PIB derivatives with amines followed by reduction with formic acid. Polyamines are among the recited reactants and the products are useful as fuel additives as noted above in connection with the Baxter et al. '285 patent.
U.S. Pat. No. 5,663,457 to Kolp teaches to prepare alkylated hydroxyl aromatics by reacting polyisobutylene with hydroxyaromatics in the presence of an acidic ion exchange resin. The products are likewise useful in or as lubricant and fuel additive compositions.
U.S. Pat. No. 5,725,612 to Malfer et al. discloses Mannich fuel additives prepared by reacting alkylated hydroxyaromatic compounds with an aliphatic polyamide and an aldehyde. Mannich reaction product fuel additives are also disclosed in United States Patent Application Publication No. US 2007/0068070 of Jackson et al. wherein the materials are prepared using a mixture of conventional and highly reactive polyisobutylene.
Lower molecular weight adducts for fuel or lubricant additives are desirable because of their higher activity on a weight or cost basis and preferred performance and viscosity characteristics in many instances. There is seen, for example, United States Patent Application Publication No. US 2012/0000118 to Lange et al. low molecular weight polyisobutyl-substituted amines as dispersant boosters. Such compounds may be prepared by hydroformylating polyisobutylene followed by reductive amination as is well known in the art. The polyisobutene precursors are noted in the publication as having a molecular weight in the range of 200 to 650 Daltons. See paragraph [0068].
Low molecular weight PIB, however, is notoriously difficult to produce, especially with both high vinylidene content and low polydispersity. See, for example, U.S. Pat. No. 5,068,490 to Eaton. Both of these properties are important for use as additives and additive presursors.
U.S. Pat. No. 5,326,921 to Chen discloses polybutenes with a molecular weight of about 600 and relatively narrow molecular weight distributions. The materials are made with aluminum chloride catalyst at a temperature of 50° C. and residence times of 30 minutes. See Table I at Cols. 13-14. At these times and temperatures the alpha and beta content of the product is conventional as seen in the commercial material discussed hereinafter. Moreover, the material is not chloride-free which is also a desirable characteristic for additives, especially because of potential corrosion caused by high chloride levels.